Last February, pedestrians walking on the Armistice Bridge would have seen the first signs of a moribund waterfront district that was beginning to come to life, as workers knocked down the crumbling concrete shell of the former Stinson sardine packing plant. They were hired by DUBBA LLC, made up of a group of Maine maritime professionals who planned to develop Front Street Shipyard as a major regional destination.

This winter, the view is very different. Four forest green buildings have risen in place of the old Stinson plant, with one stretching five stories high — big enough to do work year-round on multimillion dollar yachts. A fifth building should be completed by June 1, according to shipyard managing director J.B. Turner. Many boats, swaddled in white plastic, safely wait out the rest of winter on shore. And inside, it’s a beehive of activity as workers repair, refit and assemble boats.

Turner, who just hired his 68th employee, said that last summer he had just 20 altogether.

“We were thinking that the first winter, we’d have 25 or 30 people,” he said Friday. “Things have gone a little faster than we’d planned.”

This week, the shipyard announced that a Rhode Island boat building company would relocate its operations to Belfast. When Carbon Ocean Yachts of Bristol, R.I., moves to the shipyard’s facility, the four or five workers who head north will become Front Street Shipyard employees. Brian Benjamin, Britt Colombo and Toby Mueller, who founded the carbon fiber yacht building enterprise, will retain ownership of their separate company, Turner said.

Carbon Ocean Yachts has been working in a smaller, older facility, he said, and will be a good fit for the shipyard.

“We were looking for expertise and the very best carbon people available,” Turner said. “They’ve been working out of Rhode Island, in a smaller, older, more antiquated facility. Our facility, being state of the art, was a major attraction. There’s nothing really like this in Rhode Island. Nothing this new and this big.”

Colombo said in a press release that the move should enhance his company’s capabilities for its clients.

“Our current facility won’t be able to accommodate our future projects,” he said. “Front Street Shipyard was our first choice for a new facility because it is already making its mark as the premier yard for big boats on the east coast.”

On Friday afternoon, those words rang true in the five-story-tall Building 5, where seven large pleasure boats were carefully fitted in like giant jigsaw pieces. Workers looked tiny as they walked between the yachts, which were getting repainted, refitted and more.

Justin Wiegleb, the service manager, said that he’d been at the shipyard since August.

“It’s a lot busier than we thought we’d be,” he said.

Midway to the ceiling, a mezzanine level was home to carpenters making teak floorboards and other hard at work men and women.

“It’s nice to see the industry come to the town,” Wiegleb, of Warren, said.

Belfast City Councilor Roger Lee said he believes the shipyard’s continued, rapid growth may be helping people feel confidence in the city and its possibilities.

“It’s a catalyst. It’s something you can really point to — it’s concrete. Those jobs are coming here,” he said Friday.

It’s a change from just a few years ago, when the city suffered from an epidemic of closing businesses, Lee said.

“I don’t know what’s next. But most of the news is positive,” he said.

Belfast Development Director Thomas Kittredge said that the shipyard’s growth is adding to a burgeoning maritime industry that already featured custom shipbuilders French & Webb and the Belfast Boatyard.

“Front Street Shipyard is adding critical mass,” he said. “I think we’ll be seeing some more businesses in the next few years coming to Belfast, complementing our boat building and boat storage facilities we have already.”